Dominik spen 1/4 of his money on 9 badges and 3 key chains. The cost of each badge was 1/2 the cost of each key chain. He bought some more key chains with 2/9 of his remaining money. How many key chains did Dominik buy altogether?
K==cost of 1 key chain.
1/2*9K + 3K ==1/4M
7.5K == 1/4M
K==M / 30 - price of 1 key chain
2/9 * 3/4M ==1/6M - what he spent on buying additional key chains.
1/6M / [M / 30] ==1/6 x 30==5 additional key chains he putchased
3 + 5 ==8 total number of key chains he purchased.